Human rotavirus specific T cells: quantification by ELISPOT and expression of homing receptors on CD4+ T cells

Abstract

Using an intracellular cytokine assay, we recently showed that the frequencies of rotavirus (RV)-specific CD4(+) and CD8(+) T cells secreting INFgamma, circulating in RV infected and healthy adults, are very low compared to the frequencies of circulating cytomegalovirus (CMV) reactive T cells in comparable individuals. In children with acute RV infection, these T cells were barely or not detectable. In the present study, an ELISPOT assay enabled detection of circulating RV-specific INFgamma-secreting cells in children with RV diarrhea but not in children with non-RV diarrhea without evidence of a previous RV infection. Using microbead-enriched CD4(+) and CD8(+) T cell subsets, IFNgamma-secreting RV-specific CD8(+) but not CD4(+) T cells were detected in recently infected children. Using the same approach, both CD4(+) and CD8(+) RV-specific T cells were detected in healthy adults. Furthermore, stimulation of purified subsets of PBMC that express lymphocyte homing receptors demonstrated that RV-specific INFgamma-secreting CD4(+) T cells from adult volunteers preferentially express the intestinal homing receptor alpha4beta7, but not the peripheral lymph node homing receptor L-selectin. In contrast, CMV-specific INFgamma-secreting CD4(+) T cells preferentially express L-selectin but not alpha4beta7. These results suggest that the expression of homing receptors on virus-specific T cells depends on the organ where these cells were originally stimulated and that their capacity to secrete INFgamma is independent of the expression of these homing receptors.

Virus-specific intestinal IFN-γ producing T cell responses induced by human rotavirus infection and vaccines are correlated with protection against rotavirus diarrhea in gnotobiotic pigs

“…between IFN-γ producing T cell frequencies in blood at challenge and clinical signs post-challenge in the same pigs). Recent studies of T cell responses in human PBL showed that in rotavirus infected children, virus-specific CD4+ and CD8+ T cells that secreted IFN-γ were very low or undetectable [19,49]. Similar results were found in studies of rotavirus-infected juvenile rhesus macaques monkeys [50].…”

Intramuscular rather than oral administration of replication-defective adenoviral vaccine vector induces specific CD8+ T cell responses in the gut

“…The oral mode of delivery has the potential to confer long-term mucosal immunity against pathogens such as HIV-1 if it can induce antigen specific cells to home to the gut as shown in previous studies [25][26][27][28], but efforts to stimulate immunity through this route may inadvertently induce oral tolerance instead [29]. Oral vaccine development using replication defective adenovirus, such as the vector we have tested, may be impeded by vector instability in the acidic environment of the stomach, through which it must pass to ensure antigen presentation and maximum exposure to and uptake by the antigen presenting cells of the intestine.…”

Correlates of protection for rotavirus vaccines: Possible alternative trial endpoints, opportunities, and challenges

“…3 Similar to RV-mBc, in healthy adults RV-T cells express intestinal migration markers, suggesting that they may be reflecting intestinal RV-T cells. 89 Most children with natural infection have undetectable or very low levels of RV-T cells measured by their capacity to secrete interferon gamma upon stimulation with antigen in vitro. 90 Recent development of class II cell tetramers with RVspecific epitopes allowed detection of circulating RV-CD4 T cells that express intestinal homing receptors in healthy adults, and in children vaccinated with RIX4414.…”